Express your answer in scientific notation. $7.9 \cdot 10^7 + 6.5 \cdot 10^6 = $
Solution: $\phantom{=} {7.9 \cdot 10^7} + 6.5 \cdot 10^6$ $={79 \cdot 10^{6}} + 6.5\cdot10^{6} $ $= (79+6.5)\cdot10^{6}$ $=85.5\cdot10^{6}$ $= 8.55\cdot10^{7}$